The object of this invention is to reduce the cost of space heating with solar energy, particularly in colder climates where it is impractical to store heat for great enough periods of time to obviate the necessity for a coexistent, full-sizes, conventional heating system if comfort is to be assured. Having granted that a conventional furnace is required, the conversion of solar energy to space heat is desirable for the purpose of cost reduction or, in some cases, fuel conservation. Where fuel is in short supply, higher cost of solar energy conversion can be justified. The invention described herein was designed on the assumption that savings in heating cost are a primary consideration, and other factors are secondary, however important they may be.
This invention may be used in any space heating application, residential, commercial, or industrial, as long as there are no isolated branch heating circuits which do not interchange heat freely with a central heating system. The best use will probably be found with a central forced warm air system, although each system should be analyzed on its own characteristics.
Most present systems for heating with solar energy use water or water solutions in conjunction with storage tanks, electric heaters, various radiation and convection heat exchangers, electronic control systems, and extensive plumbing circuits. Consequently, they are not applicable to the concept of low-cost, direct-transfer, heating systems. Their main use is in conserving fuel or in gathering research data until such time as the cost of fuel rises faster than the cost of materials and labor.
Another beneficial method of using direct-transfer, air-heating systems is in conjunction with any of the commercial heat pumps which depend on warm air for the heat source. Such heat pumps generally depend on waste heat from lighting, machinery, and occupants, or else extract heat from the outdoors and lose efficiency as the ambient temperature falls. A solar collector panel which preheats the outdoor air before it enters the evaporator coil may thus have its effects magnified by increasing the performance of the heat pump.